This invention relates to a laminate cutting apparatus for automatically cutting a laminate consisting of multiple plies of a sheet material such as a fabric.
Heretofore, an automatic laminate cutting apparatus of the type mentioned above is disclosed in, for example, Japanese Patent Publication No. Sho 53-13836. In this conventional apparatus, a laminate such as a fabric to be cut is supported on a supporting surface of an air-permeable support member, and by withdrawing air from the under surface of the support member, the laminate is supported on the supporting surface in a compressed state. In that state, a knife-like cutter as a cutting tool is penetrated into the laminate from above, so that the laminate is cut into a desired shape.
The inventor of the present invention has also proposed a laminate cutting apparatus as discussed in Japanese Patent Application Laid-Open (KOKAI) No. Hei 1-306200. This conventional cutting apparatus includes a pedestal, a belt support mechanism provided with a number of belt support plates arranged in parallel in the longitudinal direction (forward and backward direction), a laminate supporting belt supported on the pedestal through the belt support mechanism and capable of reciprocating longitudinally, and a travel body supported on the pedestal and capable of reciprocating longitudinally. The travel body is provided with a recess forming member for forming a movable recess having an open upper surface in a longitudinal part of the support belt, a cutter head capable of reciprocating transversely above the support belt, and a cutter receiving sleeve capable of reciprocating transversely within the movable recess in synchronism with this cutter head. A knife-like cutter is mounted on the cutter head with its tip portion inserted into the cutter receiving sleeve such that the cutter is capable of moving up and down. The pedestal is provided on both sides thereof with suction ducts having suction ports opening up at their opposing surfaces.
With this cutting apparatus, an air-permeable laminate such as a fabric, which is covered at all surfaces excepting side surfaces thereof with an air-impermeable sheet, is supported on the supporting belt, and air is withdrawn from both side surfaces of the laminate through the suction duct, so that the laminate is held in a compressed state on the supporting belt.
In that state, the cutter is lowered to insert its tip portion into the cutter receiving sleeve, the cutter head is reciprocated transversely, and the travel body is reciprocated longitudinally, whereby the laminate is cut into a desired shape.
The belt support mechanism has a cam plate and the belt support plates each of which is provided with an elevating mechanism. This elevating mechanism is provided with rack bars each having a round shape in section. The rack bars are hung down from two transverse locations of the under surface of the belt support plates respectively. Pinions meshed with the rack bars are fixedly secured to both end portions of a connecting shaft which, in turn, is rotatably horizontally supported by a support plate retaining member secured to the pedestal through a bearing. The connecting shaft is provided with a brake. The brake is operated to be released, only when necessary, by means of electrical control using electricity, air, hydraulic pressure, etc. Usually, the connecting shaft is locked to the retaining member so that the support plate can maintain its raised state. The retaining member is provided with a clamp member adapted to slidably support the rack bars.
For moving the movable recess, the support plates, which support the under surface of the supporting belt at a front location of the travel body, is brought into a state able to be lowered owing to release of the brake caused by suitable means for detecting approach of the cam plate which is secured to the travel body under traveling. Subsequently, rollers rotatably attached to the support plates are brought into engagement with a cam groove, which is formed in the cam plate, in accordance with traveling of the travel body. As traveling of the travel body proceeds, the support plates, while maintaining their horizontal postures, are lowered below the movable recess. The support plates located below the movable recess are raised, one after another, first from one located behind guided by the cam groove in accordance with traveling of the travel body. When the support plates are separated from the cam plate, they support the under surface of a supporting portion of the supporting belt. In that state, the brake stops its releasing action to lock the raised position, and then this locked state is maintained. Therefore, in accordance with the movement of the movable recess, the support plates, which are bought below the movable recess, are gradually changed one after another. Simply with the change of the support plates, only the support plates corresponding longitudinally to the cam plate are located below the movable recess and the under surface of the supporting belt is normally supported by the number of remaining support plates.
Since the laminate cutting apparatus shown in the afore-mentioned Publication No. Sho 53-13836 is a cantilever type cutter in which the laminate retained in a compressed state on the supporting surface by suction is penetrated by the knife-like cutter and the tip portion of the cutter is also penetrated in the area near the supporting surface of the support member, the tip portion of the cutter is twisted by resistance of the laminate and support member. The result is that a cut product of high accuracy is difficult to obtain. A band saw type cutter is sometimes used as a cutting tool. In this case, however, when the laminate is cut by the cutter, the laminate and the support member are simultaneously cut by the cutter. Since it is necessary to change the support member highly frequently, the working ratio is bad.
On the other hand, the laminate cutting apparatus disclosed in the second-mentioned Publication No. Hei 1-306200 is complicated in structure because the belt support mechanism for supporting the laminate supporting belt has the belt support plates provided with the rack bars, the pinions and the brakes. Moreover, since the brakes are controlled by the electrical means, there is a fear that failures are likely to occur.